The present invention relates to a laminated arrester and a manufacturing method therefor. The manufacturing method means manufacturing of an arrester via the assembly process at factory and also assembling of an arrester at the job site.
Power is generated by a nuclear power station, hydraulic power station, or thermal power station in the distance and transmitted to a substation in the neighborhood of the demand site at a long distance and high voltage via aerial cables. Aerial power transmission often passes through mountainous regions and may be affected by an abnormal voltage due to a thunder phenomenon among natural phenomena. If aerial transmission is struck by lightning and a transmission and transformation device, for example, a gas insulating switch (GIS), transformer, breaker, or disconnecting switch is affected by an abnormal voltage and subjected to dielectric breakdown by an overvoltage, the power system is grounded, and the transmission and transformation device is damaged, and power transmission is made impossible.
Therefore, an arrester is installed in the power system as an overcurrent suppressor. It is required recently to scale down the transmission and transformation device due to a rise in land price. For example, a zinc oxide type arrester for gas insulating switch in which zinc oxide elements for switch are set in SF6 insulating gas is used so as to scale down the transmission and transformation device. Basically in the zinc oxide arrester, zinc oxide elements are overlaid in series and doughnut-shaped zinc oxide elements are fixed by an insulating bar and cylinder and arranged in gas, for example, SF6 gas in a straight line.
For a high voltage, when the arrangement constitution that a plurality of zinc oxide elements are laminated in a straight line is used, the arrester becomes longer and cannot be suited to an arrester to be connected to the gas insulating switch. Therefore, in the arrester indicated in Japanese Patent Application Laid-Open No. 56-91402 and Japanese Patent Publication No. 62-44681, a plurality of laminated element columns having many laminated zinc oxide elements are arranged in parallel and the laminated elements are electrically connected to each other so as to reduce the height of laminated elements. In the arrester indicated in Japanese Patent Application Laid-Open No. 61-125001, a horizontal type of arrester is used so as to solve the problem that it is difficult to apply an arrester which is made longer due to laminated zinc oxide elements to the gas insulating switch.
The assembly method for a zinc oxide arrester to be installed in the grounding tank is such that, as indicated in Japanese Patent Application Laid-Open No. 55-105989, in the case of vertical type, a lamination type arrester unit having a plurality of laminated zinc oxide elements is arranged on the tank sealing cover, and the grounding tank which is lifted up by a crane or others beforehand is moved down from above so as to cover the lamination type arrester unit, and the tank opening is made in contact with the cover so as to seal the tank hermetically. The assembly method for a horizontal type of arrester is such that the tank is assembled vertically in the same way as with the vertical type arrester and the finished arrester is turned and laid on its side.
However, as the power system increases in voltage, arresters become large and heavy and the assembly of arresters becomes difficult and dangerous.